The present disclosure relates to a mechanism usable for collecting information from a local sensor network, such as a wireless sensor network, by means of a communication network element, such as a user equipment, functioning as a gateway to the local sensor network. In particular, the present disclosure is related to a mechanism for accessing a local sensor network via a gateway in order to be able to collect information from the local sensor network at a sink node.
The following meanings for the abbreviations used in this specification apply:
BC: Beacon Cluster
CH: Cluster Head
eNB: evolved Node B
ID: Identification
LTE: Long Term Evolution
LTE-A: LTE Advanced
SN: Sensor Node
UE: User Equipment
WSN: Wireless Sensor Network
In the last years, an increasing extension of communication networks, e.g. of wire based communication networks, such as the Integrated Services Digital Network (ISDN), DSL, or wireless communication networks, such as the cdma2000 (code division multiple access) system, cellular 3rd generation (3G) communication networks like the Universal Mobile Telecommunications System (UMTS), enhanced communication networks based e.g. on LTE, cellular 2nd generation (2G) communication networks like the Global System for Mobile communications (GSM), the General Packet Radio System (GPRS), the Enhanced Data Rates for Global Evolutions (EDGE), or other wireless communication system, such as the Wireless Local Area Network (WLAN) or Worldwide Interoperability for Microwave Access (WiMAX), took place all over the world. Various organizations, such as the 3rd Generation Partnership Project (3GPP), Telecoms & Internet converged Services & Protocols for Advanced Networks (TISPAN), the International Telecommunication Union (ITU), 3rd Generation Partnership Project 2 (3GPP2), Internet Engineering Task Force (IETF), the IEEE (Institute of Electrical and Electronics Engineers), the WiMAX Forum and the like are working on standards for telecommunication network and access environments.
Information sharing between different types of network entities drives the aggregation of heterogeneous networks. This kind of aggregation provides for example the possibility to exchange information between entities of a local network and a heterogeneous network.
A specific example for a combination of capabilities of different networks for information sharing is to use a cellular network element such as a user equipment or entity (UE) as a gateway for a local sensor network, such as a wireless sensor network. That is, elements of a cellular network and a wireless sensor network are mixed so as to easily expand the function of each network.
A WSN as an example for a local sensor network may consist of spatially distributed autonomous sensors which are configured to monitor different parameters, such as physical or environmental conditions like temperature, sound, pressure, movements, concentrations of specific elements in the air etc. The sensor nodes are further configured to cooperatively pass data through a network to a main location which is also referred to as sink. Also bi-directional communication between the sensor nodes and the sink is possible to as to enable a control of the sensors, for example. WSNs are used, for example, in many industrial and consumer applications, such as industrial process monitoring and control, machine health monitoring, environment and habitat monitoring, healthcare applications, traffic control and the like. The nodes of the WSN may comprise sensor nodes (SN) and one or more cluster head (CH) nodes. Cluster head nodes are used as managing nodes when a WSN is divided in one or more clusters containing plural sensor nodes and one cluster head node. The sensor nodes are connected to one (or sometimes several) other sensor nodes, wherein their data are forwarded to a respective cluster head which transmit the aggregated information to the sink. A sensor node has typically several parts: a transceiver with an antenna or connection to an antenna, a microcontroller, an electronic circuit for interfacing with the sensors and an energy source, e.g. a battery or an embedded form of energy harvesting. The topology of a WSN can vary from a simple star shape to a multi-hop mesh network.
Usually, in a WSN, the sink is local device for collecting data of whole network, wherein each network deploys a local sink. It is possible that a sink can communicate with other sinks via the Internet, if necessary, for example in order to obtain information of other sensors not being associated to the network of this sink. That is, conventional WSN may be connected via the Internet in order to achieve the goal to share information.
However, data collection efficiency in this case is rather low in terms of the fixed sink. This could be overcome, for example, by increasing the number of sinks, but this would actually lead to a further division of the local network into several parts, which may increase costs and complicates the managing of the sensor networks as a whole.
There have been proposed several attempts to improve the linking between cellular networks and WSNs. One reason for this is that there is a contradiction between the usual function of a communication network element of the cellular network and a function of a sink node in WSN. For example it has been tried to optimize the selection of cluster heads to meet specific constraints, but there are still open questions how to overcome problems with regard to computation and communication overheads incurred by re-clustering.
There has been also proposed a so-called Complete Graph-based Clustering Algorithm (CGCA) which is applicable in a densely deployed sensor network. According to this approach, the network is divided into a few complete graphs, each complete graph independently being a cluster.